Add node modules and new code for release (#57)

Co-authored-by: taakleton <taakleton@users.noreply.github.com>

node_modules/@sinonjs/commons/lib/value-to-string.test.js

@@ -0,0 +1,20 @@
+"use strict";
+
+var assert = require("@sinonjs/referee-sinon").assert;
+var valueToString = require("./value-to-string");
+
+describe("util/core/valueToString", function() {
+    it("returns string representation of an object", function() {
+        var obj = {};
+
+        assert.equals(valueToString(obj), obj.toString());
+    });
+
+    it("returns 'null' for literal null'", function() {
+        assert.equals(valueToString(null), "null");
+    });
+
+    it("returns 'undefined' for literal undefined", function() {
+        assert.equals(valueToString(undefined), "undefined");
+    });
+});